5.21. Set Up:Take to be upward. After he leaves the ground the person travels upward 60 cm and hisacceleration is downward. His weight is Wso his mass is Solve: (a)(at the maximum height),gives(b)The free-body diagram for the person while he is pushing up against the ground is given in Figure 5.21.Figure 5.21(c)For the jump,(from part (a)),gives gives Reflect:To accelerate the person upward during the jump, the upward force from the ground must exceed the down-ward pull of gravity. The ground pushes up on him because he pushes down on the ground.5.22. Set Up:Let the acceleration be in the direction.Solve: (a)Apply to the four cars taken as a single object. The free-body diagram for this object is givenin Figure 5.22a. mis the mass of one car and is the force that the engine exerts on the first car.Figure 5.22gives and (b)Applyto the last three cars taken as a single object. The free-body diagram for this object is givenin Figure 5.22b. is the force that the first car exerts on the second car. gives
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This note was uploaded on 03/06/2009 for the course PHYS 114 taught by Professor Shoberg during the Spring '07 term at Pittsburg State Uiversity.